Transformer and connection for starting arc lamps



28, 1948 D. REICHINSTEIN 2,457,494

TRANSFORMER AND commoner: FOR STARTING ARC Lmrs Filed March 28, 1944 v 2 Sheets-Sheet 1 59 \J MAM/WW Fig. 2

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Dec. '28, 1948. D, REICHINSTEIN 2,457,494

TRANSFORMER AND CONNECTION FOR STARTING ARC LAMPS Filed March 28. 1944 2 Sheets-Sheet 2 Patented Dec. 28, 1948 TRANSFORMER AND CONNECTION FOR STARTING ARC LAMPS David Reichinstein, Zurich, Switzerland, assignor to Fanal Licht A.-G., Lucerne, Switzerland Application March 28, 1944, Serial No. 528,420 In Switzerland September 30, 1942 Section 1, Public Law 690, August 8, 1946 Patent expires March 8, 1963 There are current consuming appliances which have to be started by high voltage, the current intensity required being comparatively small, whilst almost immediately upon starting there is a drop in the voltage of the appliance. Among such appliances may be mentioned the arc lamp with electrodes separated by fixed intervals. A high voltage is required for their ignition, whilst the terminal voltage of the lamp drops very shortly after ignition. Such are lamps were formerly started with the help of alternating current by using on the one hand leakage transformers, i. e. transformers in which voltage is dropping simultaneously with the increase in current intensityand on the other hand reactance coils taking up voltage without energy.

The present invention constitutes a substantial improvement on these methods by affording a suitable method for regulating to lower voltage and high intensity the feeble current, generated by high voltage, flowing through the arc lamp after it has been ignited-without having to interrupt the current.

This method is based on the investigation of the curve representing the dependence on the eiiective current intensity of the fixed effective terminal voltage of the lampindependent from timein this case therefore the independent variable. As we know, this curve is called the static characteristic of the arc lamp. An example will help to understand more clearly the present process: A lamp was ignited at 2400 volts, the inductive reactance of the circuit under consideration being such that upon ignition an eifectivecurrent intensity of 0.1 ampere prevails there. Now, if we wish to switch over to, say, 400 volts, this is only possible under the following conditions:

(1) The static characteristic must show that at 0.1 ampere the terminal voltage of the arc lamp is less than 400 volts;

(2) In changing over the current intensity must not for ever so short a time drop below 0.1 ampere, nor must the current be totally interrupted, in order that the terminal voltage shall not rise above 400 volts, but for the purpose of reliability of the operation of switching over it must be higher than 0.1 ampere in the new circuit.

The transformer arrangement of the present invention is characterised by the fact that the secondary winding of the transformer consists of several parts of various wire diameters, and that such parts of this winding as consist of wires of small diameters can be bridged over by nieans of impedances, and completely put out 1 Claim. (Cl. 31596) 2 of circuit by means specially provided for this purpose.

Each winding, however, must admit of such a current intensity as, according to the static characteristic of the arc lamp, is required in order to be able to change over to the next lower voltage.

In the drawings A constructional example of the subject of the present invention is given in Fig. 1 which shows a wiring diagram.

Fig. 2 is a wiring diagram of a modified construction;

Fig. 3 is a wiring diagram of the entire lampigniting system;

Fig. 4 illustrates a wiring diagram of a modified lamp-igniting system.

A transformer has been selected as example, connected with such a lamp, requiring for its starting approximately 2400 volts, whilst 0.1 ampere suflices for the purpose and on the other hand its regular working requires a current of several amperes at a voltage below volts. Furthermore, this lamp shall present the following characteristics: With 0.1 ampere the voltage drops from 2400 volts to less than 400 volts, whilst with 0.3 ampere a drop of voltage down to less than 100 volts must be brought about. The three steps of the transformer are connected in series in such a manner that the winding supplying the lowest voltage is placed in the middle.

The numerals of Figure 1 of the drawing have the following meaning:

l-2: Terminals of the primary coil of the transformer.

3-6: Terminals of the secondary coil of transformer.

3'4: Part of the secondary coil supplying, with a network voltage of 200 volts, a secondary voltage of 300 volts; this part of the transformer shall be of a size suitable for 0.3 ampere.

4-5: Another part of the secondary coil supplying a voltage of 100 volts, of a size suitable for approximately 5 amperes; this part of the transformer remains in circuit in normal service.

5-6: A further part of the secondary coil, with a network voltage of 200 volts, a voltage of 2000 volts, of a size suitable for 0.1 ampere.

I, 8, 9, l0: Current switches.

II: Lamp.

l2: An ammeter.

l3: An adjustable resistance inserted in the lamp circuit.

[4 and i5: Fixed'resist'ances calculated as follows: The resistance of I5 must be such as,

the

together with ohmic resistances of the windings, as well as of M and the apparent ohmic resistance of the lamp, to prevent the current intensity of 0.1. ampere from being exceeded at the voltage of 2400 volts; practice has shown the following values to be sufficient in the case under consideration: I-approximately 20,000 ohm; l4approximately 1000 ohm. Induc tances or capacitances maybe used place of resistances. In order to start the'lamp, 9 and I!) must be closed whilst I and 8 are open. 8 is then closed Iii-l1: Terminals of the primary coil of the transformer. l8-2l: Terminals of the secondary coil of the transformer. I8l9: Terminals of the service transformer.

l9.-20 and 25-2l: Represent those parts of the transformer that can be put out of circuit. 22, 23, 24: Adjustable impedances. 25, 26, 21, 28: Current switches. 29.: The arc lamp.

' 38: An ammeter.

In order to ignite the lamp, the variable, incpedance 22 is to a large extent put in circuit, and

' the switches 21, 28 opened, whilst 25 26 are closed.

In order to out 01f the transformer part 20+2l, this part is first closed by closing the switch 28 over the impedance 24, after which this transe former part is cut on by opening the switch 26. 24 can now be cut off by displacing it the trans- 1 former part l9-20 is likewise eliminated by close ing 27, opening 25 and displacing 23..

part of thei 4 cuited, and on the other hand making possible the adjustment in each special case of the current intensity required to change over the are on to the lowest voltage step 35--36, max- 80 ohm and 3 amperes.

85: Is the retactance coil setting the limiting current intensity, i. e. the intensity above which the electrodes begin to melt.

49: Is the regulating resistance in normal services; inthose cases in which a regulation is not required, 49 could be dispensed with, and 48 selected was to suit continuous service.

'53: Is the series resistance by means of which 1 the, current of. the, auxiliary arc can be reduced; it. can'be short-circuited by means of the switch 4.5; in case the distance between the auxiliary electrode and the main electrode is sufiiciently great, 53 can be dispensed with; experience, however, has shown that in order to ensure reliability of ignition this interval must be small, thus requiring the use of 5.3.; in the practical case, here, under. consideration, i3. amounted to 920 ohm with a maximum load of 0.4 ampere.

52: .Is a small adjustable resistance below 1 ohm,

enabling the heating of 55 to be limited.

4|, 42, 33, 44, 45., 4.6, 41: Are currentv switches.

56': Is an ammeter.

5.4: Is the arc lamp.

According to the drawing the four secondary coils together with the network tension. 01.220

volts are connected in series. so that the available maximum. voltage amounts to 640 volts. The ignition is initiated as follows: 42, 23., 44, 45, are. closed, whilst 56 and 4.7 are opened. By Closing,

, 4| the transformer is now connected to thenet- The whole connecting system which makes it possible to ignite the lamp and put it in service at low voltage is shown in Fig. 3 and explained by the following practical constructional example: The significance of the letters and numerals is as follows:

. A, B: The public network of say 220 volts. 31-32: The primary coil of the transformer. 33-40: 4 secondary coils of the transformer,

work, and at the same time the. network connected in series with the secondary coils. The, auxiliary electrode 5.5 which is described more fully in my co-pending patent application,,.Serial. No. 527,053, filedMarch 18, 19.44,, begins to, glow and there arises atonce an are between the; aux iliary electrode and the main electrode 54 which has been heated by the incandescence of the. electrode 55. The switch 54. is. then opened, causingt incandescent wire to. be extinguished, whilst. its are still increases in intensity causing the; one,

main electrode to. become incandescent, wheree.

upon is, opened; the-main electrodes are soon, ignited and the auxiliary arc extinguished; 4.6 is now closed and 42 opened, after which. a tension of 200 volts prevailsin thecircuit; finally, 41 is closed and 43 opened, whereby on, the one hand, the arc is switched. over to volts, and. on the other hand the, common pole 5.! switched off coil 39, 4.0; the auxiliary electrode, with its two poles.

connected in series; these shall be more particularly described.

3 334-.: Supplies, with the public network of 220 volts, a voltage of 200-volts and admits of taking out 1.5 ampere.

35-36: Supplies under the same conditions 50 volts and admits of a load of 20v amperes.

3 .1.38': Supplies under the same conditions 150 volts and 3 amperes.

$35-40: Supplies 20 volts and 20 amperes; this;

secondary coil constitutes the current source required for heating the, incandescent wire of the auxiliary electrode 5|: Is the series resistance limiting the ignition current intensity; in the practical case under considerationit amounts to 410 ohm, and admits of a load of 1.5 ampere.

50.; Is an. adjustable resistance enabling on, the one hand. the 37-40 voltage to be short-ciris now switched off the current source by which it was heated, and practically connected. with the main electrode only through thesumof the resistances 5.5 and 53; it need hardly be mentioned that, with a current source or 50 vol-ts. and aresistanceof 1000 ohm, an arccan under no conditions be either ignited or subsist. It is. turthermore obvious. that in service there is no need.

to operateindividually each of the. 7 switches;

this is done in one. single. operation by. means. of a drum switch. The electrodes 54 and 55. and their location are indicated diagrammatically, in the. drawing.

we now consider an arc lamp. inyolving, no auxiliary are, but including a, heating: wirewound round the main electrodes and completely in sulated, from the latter, the system of connections is. modified according, to 4,.in such. manner I that the. secondary coils. 31-38. and'39--40. are.

separated. 55 now represents the heating wire wound round the main electrodes which can be connected to the secondary coil 39-40 by means of the switch 44 and of the adjustable impedance 52. It may be mentioned here that in the prac tical case under consideration the voltage available for the ignition of the main electrodes amounts to 620 volts, not 640 volts. The drum switch closes for a short time the switch 44, after which-as mentioned above-46 is closed and 42 opened, and finally 4'! closed and 43 opened.

I claim:

A system for the starting of an arc lamp, said system comprising, in combination, a transformer having a primary winding connected to a source of alternating electrical current, and a plurality of secondary winding coils having at least three intermediate terminals and two end terminals, said coils constituting in their entirety a second ary winding supplying high lamp-igniting voltage, means connecting one terminal of the arc lamp to said source and comprising a resistance, means connecting the other terminal of the arc lamp to an end terminal or the secondary winding coils and comprising a switch and a resistance in series therewith, means connecting the other end terminal of the secondary winding coils to the primary winding, an auxiliary electrode for heating the electrodes of the arc lamp, means connecting one terminal of said auxiliary electrode to an intermediate terminal of the secondary winding coils and comprising a switch and a resistance in series therewith, means connecting the other terminal of the auxiliary electrode to the firstmentioned switch and comprising a resistance and a switch short-circuiting said resistance, means connecting the first-mentioned means to another intermediate terminal of the secondary winding coils and comprising a switch, and means connecting the second-mentioned means to a third intermediate terminal of the secondary winding coils and comprising a switch.

DAVID REICHINSTEIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

